1. Technical Field
This disclosure relates to an outdoor unit of an air conditioner and an air conditioner.
2. Description of the Related Art
A conventional multi-chamber air conditioner includes, for example, at least one outdoor unit, a plurality of indoor units, and a refrigerant pipe that couples these members together. As this multi-chamber air conditioner, for example, there is known the air conditioner described in Japanese Patent No. 5463995 and the air conditioner described in JP-A-2005-337659. In the former air conditioner, all the indoor units perform cooling operation or heating operation. The latter air conditioner can perform what is called cooling/heating-free operation in which each indoor unit can selectively perform cooling operation and heating operation.
In the air conditioner disclosed in Japanese Patent No. 5463995, a plurality of outdoor units and a plurality of indoor units are coupled to one another by liquid pipes and gas pipes. All the indoor units perform any one of cooling operation and heating operation. On the other hand, in the air conditioner disclosed in JP-A-2005-337659, an outdoor unit, a plurality of indoor units, and the identical count of branching units to that of the indoor units are coupled to one another by liquid pipes, high-pressure gas pipes, and low-pressure gas pipes. Each indoor unit can selectively perform cooling operation or heating operation. In the following description, the air conditioner that includes a liquid pipe and a gas pipe as refrigerant pipes for coupling an outdoor unit and an indoor unit together is referred to as a double-pipe air conditioner. The air conditioner that includes a liquid pipe, a high-pressure gas pipe, and a low-pressure gas pipe as refrigerant pipes for coupling an outdoor unit and an indoor unit together is referred to as a triple-pipe air conditioner.
Now, the double-pipe air conditioner and the triple-pipe air conditioner differ in structure from each other. Specifically, the double-pipe air conditioner includes two pipes of the liquid pipe and the gas pipe as the refrigerant pipes for coupling the outdoor unit and the indoor unit together. Accordingly, the outdoor unit internally includes an outdoor-unit liquid pipe, which couples the liquid pipe and an outdoor heat exchanger together, and an outdoor-unit gas pipe, which couples the gas pipe and a four-way valve together.
On the other hand, the triple-pipe air conditioner includes three pipes of the liquid pipe, the high-pressure gas pipe, and the low-pressure gas pipe as the refrigerant pipes for coupling the outdoor unit, the indoor unit, and the branching unit to one another. Accordingly, the outdoor unit internally includes an outdoor-unit liquid pipe, an outdoor-unit high-pressure gas pipe, and an outdoor-unit low-pressure gas pipe. The outdoor-unit liquid pipe couples the liquid pipe and the outdoor heat exchanger together. The outdoor-unit high-pressure gas pipe couples a discharge pipe, which is coupled to a discharge side of a compressor, and the high-pressure gas pipe together. The outdoor-unit low-pressure gas pipe couples an intake pipe, which is coupled to an intake side of the compressor, and the low-pressure gas pipe together. As just described, in the triple-pipe air conditioner, a refrigerant circuit is formed by coupling the outdoor unit to the indoor unit and the branching unit using the three refrigerant pipes. On the other hand, in the double-pipe air conditioner, a refrigerant circuit s formed by coupling the outdoor unit to the indoor unit using the two refrigerant pipes. Accordingly, it is difficult to use the outdoor unit of the triple-pipe air conditioner as the outdoor unit of the double-pipe air conditioner.
Regarding the use of the outdoor unit of the triple-pipe air conditioner as the outdoor unit of the double-pipe air conditioner, for example, the following configuration is possible. That is, the outdoor unit includes the first four-way valve and the second four-way valve. The second four-way valve couples to the gas pipe, the outdoor-unit high-pressure gas pipe, and the outdoor-unit low-pressure gas pipe. It is possible to switch the second four-way valve so as to selectively couple any of the outdoor-unit high-pressure gas pipe and the outdoor-unit low-pressure gas pipe to the gas pipe. Switching the second four-way valve allows guiding the low-pressure refrigerant that flows in from the gas pipe during cooling operation into the outdoor unit or allows the high-pressure refrigerant that is discharged from the compressor during heating operation to flow out from the outdoor unit to the gas pipe. Accordingly, the outdoor unit of the triple-pipe air conditioner can be used as the outdoor unit of the double-pipe air conditioner.